• Clinical features of uveitis vary depending on the location of the inflammation. They include:
• Pain in one or both eyes (pain may be worse when the person is reading and otherwise contracting the ciliary muscle).
• Red eye (this is not always present).
• Diminished or blurred vision (although vision may be normal but become impaired later).
• Watering of the eye.
• Photophobia.
• Flashes and floaters.
• An unreactive or irregular-shaped pupil resulting from previous attacks (although this is not easy to see in primary care).
• Symptoms may develop over hours or days (acute uveitis), or onset may be gradual (chronic uveitis).
• If the person has had uveitis before, they may feel the symptoms coming on before the signs are present.
• People with chronic uveitis are more likely to experience milder inflammatory symptoms:
• Mildly red eye or normal-looking eye.
• Mild pain with photophobia.
• Uveitis is more likely if the person has risk factors for uveitis (for example a history of attacks) and other eye conditions have been excluded.
• If uveitis is suspected, refer the person to an ophthalmologist for same-day assessment to confirm the diagnosis and for treatment.
• Uveitis cannot be diagnosed without slit-lamp examination.
• Slit-lamp examination will show inflammatory cells that may aggregate to form 'snowballs'.

When to suspect uveitis

• The information on when to suspect uveitis is based on two standard reference textbooks, Ophthalmology [Forster, 2009] and ABC of eyes [Khaw et al, 2004], and published expert opinion [Gupta and Murray, 2006; Gutteridge and Hall, 2007].

Symptoms and signs vary depending on the location of the inflammation

• The statement in that symptoms and signs vary depending on the location of the inflammation is based on expert opinion from an online textbook [Merck, 2008].

Findings on slit-lamp examination

• The statement that slit-lamp examination will show inflammatory cells, which may aggregate to form 'snowballs' is derived from a textbook [Moorthy and Jampol, 2009; Tsai and Rao, 2009].

• Other serious sight-threatening conditions:
• Acute glaucoma — causes markedly increased intraocular pressure; it presents with pain in the eye, headache, and blurring of vision. Signs include:
• Ciliary injection.
• Eye feels rock hard and very painful.
• Fixed and mid-dilated pupil.
• Hazy cornea.
• Headache and vomiting.
• Markedly diminished vision.
• Keratitis — presents with a unilateral, painful, photophobic, injected eye. Signs include:
• Ciliary injection.
• Corneal ulceration — often seen as a white spot (ulcer may be dendritic when caused by herpes simplex).
• Visual impairment may be affected, depending on the site of the ulcer.
• Scleritis — characterized by severe pain. It is usually associated with headache; autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus; infections (rarely); and chemical injuries (rarely).
• Ocular trauma
• Penetrating eye injury or embedded foreign body.
• Acid or alkali burns to the eye.
• Non-sight-threatening causes
• Episcleritis — this is painful but essentially self limiting. Scleritis is much more serious.
• Infective conjunctivitis — this is more likely when:
• There is a history of close contact with another affected person.
• Symptoms of upper respiratory tract infection are present.
• The eyes are glued together by discharge after sleep, or mucopurulent discharge is seen on examination.
• Symptoms start in one eye then spread to the other.
• An enlarged lymph node in front of the ear is identified.
• Irritant conjunctivitis is likely when conjunctivitis is associated with an identifiable mechanical or irritant cause, such as a displaced contact lens, a foreign body or eyelashes rubbing against the surface of the eye, or a chemical splashing into the eye.
• Allergic conjunctivitis is likely when conjunctivitis is associated with itching and recurs after exposure to a known allergen.
• Superficial corneal injury is likely when eye pain follows trauma or possible trauma, and a foreign body is present. It is confirmed when an abrasion is seen after staining with fluorescein.
• Subconjunctival haemorrhage is asymptomatic and, other than redness, there are no other abnormal findings. The redness is well demarcated, does not cover the cornea, and obliterates conjunctival blood vessels.
• Rare neoplastic syndromes which mimic intraocular inflammation (masquerade syndromes), such as:
• Lymphoma.
• Leukaemia.
• Ocular melanoma.
• Metastases.

[Khaw et al, 2004; Yanoff and Duker, 2004; Gupta and Murray, 2006]